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OBD:Instance file format: Difference between revisions
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(I'm guessing that no one ever looked closely at this "signature" before, but it's actually more useful than that; explaining total checksum a little more) |
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The '''version''' of the instance file is the format version. Reading it backwards, as discussed under the "Backwards and garbage data" section, we get "VR31", which is probably "version 31". This is the format version of all instance files in all releases of Oni, regardless of file scheme. | The '''version''' of the instance file is the format version. Reading it backwards, as discussed under the "Backwards and garbage data" section, we get "VR31", which is probably "version 31". This is the format version of all instance files in all releases of Oni, regardless of file scheme. | ||
The ''' | The '''descriptor sizes''' are the sizes of the instance, template, and name descriptors which are coming up in this file (see breakdowns in later sections). For instance, each instance descriptor will be 0x14, or 20 bytes, in length. | ||
The '''descriptor counts''' are the sizes of arrays which are coming up | The '''descriptor counts''' are the sizes of arrays which are coming up in this file: the instance, name and template descriptors. For instance, the size of the instance descriptor array will be 0x2483, or 9,347 items, in length. | ||
Next we are told the addresses and sizes of the '''data and name tables''' in the instance file. The name table simply follows the data table, as you'll see if you add the data table offset plus the data table size, but that doesn't mean the name table offset is redundant; if its start was not 32-bit-aligned, it probably would be moved down to start at the next 32-bit word, but this is unnecessary because it happens to be aligned already. | Next we are told the addresses and sizes of the '''data and name tables''' in the instance file. The name table simply follows the data table, as you'll see if you add the data table offset plus the data table size, but that doesn't mean the name table offset is redundant; if its start was not 32-bit-aligned, it probably would be moved down to start at the next 32-bit word, but this is unnecessary because it happens to be aligned already. | ||